Purpose :
The retinal blood vessel arborization (RBVA) refers to the overall organization of the retinal arterial and venous vasculature from the optic nerve head (ONH) to the ora serrata (OS). The RBVA was once claimed to be unique to each individual (Simon & Goldstein, 1935). This claim was put to test by examining if members of the same pedigree shared common RBVA features.

Results :
RBVA analysis was limited to blood vessels found within the ONH. We identified 6 patterns of RBVA: 1-Sharp outgrowth of the central vein from the center of the ONH towards the macula, 2-Obtuse angle made by the inferior temporal vein also pointing towards the macula, 3-Inferior ventral artery and vein exiting the ONH in parallel and forming an obtuse angle pointing away from the macula, 4-Outgrowth of the central artery towards the macula circled by the central vein, 5-A“K” shape made from the four branches [inferior temporal (IT), inferior nasal (IN), superior temporal (ST) and superior nasal (SN)] of the central artery, and 6-A double “Y” shape made by the four branches (ST+SN: upright Y and IT+IN: upside down Y) of the central artery. These patterns were seen in 11%, 4.8%, 2.9%, 8.8%, 1.7% and 3.1% of our sample population, respectively. Patterns 1,2,3,5 were most frequently observed among siblings, pattern 4 among unrelated individuals and pattern 6, between two generations. Patterns 1,4 were seen significantly more frequently in both eyes than in one eye only.

Conclusions :
Our results are the first to demonstrate: 1-Easily identifiable RBVA features at the ONH, and 2-That these traits are shared by relatives at higher frequency than that predicted from the general population. Of interest, our sample included homozygous twins who had a nearly identical pattern 1 while the remainder of their RBVA (i.e. from the ONH to the OS) showed less than 31% of overlap. Thus, when one considers the entire retina (ONH to OS) the RBVA appears to be unique to one individual. However, when one only considers the RBVA within the ONH, some features of it appear shared by individuals of the same pedigree, suggesting that some aspects of the RBVA are inheritable.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.